Comment by anon9u7255

From what I remember from working in the industry many years ago, the process is actually split into (at least) 3 parts.

1. Reservation

2. Booking

3. Ticketing

Each step has its own expiration dates set by the airline, which can range from "instant" to several days/weeks. They may also set different cancelation fees for each step. A smart travel agent could in theory use this to cancel an old booking and book again if the price is reduced, but I think some airlines have changed their practice to avoid this.

Keep in mind that I mostly worked for the European market. I know US airlines operate a bit differently from the rest of the world. They usually have more flexible rules around flights and exchanging of tickets.